Method for crushing metal turnings

ABSTRACT

In the crushing of metal turnings, the turnings are first passed through a centrifugal separating drum where the fines and solid chunks are separated from the clusters of turnings. The chunks are removed, and the clusters of turnings are then passed to a shredding apparatus, which includes an endless chain conveyor, mounting teeth for advancing the clusters of metal turnings towards the crusher or pulverizer and stationary teeth spaced above the conveyor and cooperating with the teeth on the conveyor for shredding the large clusters of metal turnings as they are advanced towards the crusher or pulverizer.

ilited States Goldberg atent June 6,1972

[54] METHOD FOR CRUSHING METAL TURNINGS [72] Inventor: A. GeorgeGoldberg, Montreal, Quebec,

Canada [73] Assignee: I. l. Selig & Sons Ltd., Ville La Salle,

Quebec, Canada [22] Filed: July 22, 1970 [21] Appl. No.: 57,049

[52] U.S.Cl..1 ..241/24, 241/29 [51] Int. Cl. 1 1 ..B02c 21/00 [58]Field ofSearch ..241/24, 29, 30, 68,81,200

[56] References Cited UNITED STATES PATENTS 1,618,721 2/1927 Norman..241/81 X 2,663,228 12/1953 Serpas Neely ..24l/81 Gates .241/200 XPrimary Examiner-Granville Y. Custer, Jr. Attorney-Alan Swabey ABSTRACTIn the crushing of metal tumings, the turnings are first passed througha centrifugal separating drum where the fines and solid chunks areseparated from the clusters of turnings. The chunks are removed, and theclusters of turnings are then passed to a shredding apparatus, whichincludes an endless chain conveyor, mounting teeth for advancing theclusters of metal turnings towards the crusher or pulverizer andstationary teeth spaced above the conveyor and cooperating with theteeth on the conveyor for shredding the large clusters of metal turningsas they are advanced towards the crusher or pulverizer.

2 Claims, 11 Drawing Figures PATENTEUJUH 6&872 3,667,691

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ATTORNEY BACKGROUND OF INVENTION l. Field of Invention The presentinvention relates to a method and apparatus for reducing metal tumingsto fines which can be economically handled and remelted. 2. Descriptionof the Prior Art Metal turnings, that is the waste metal formed bydrilling, milling, or machining metal, is naturally very difficult tohandle, since it clusters in bushy bunches which have a relatively lowweight per unit volume as compared to solid scrap for example.Furthermore, the material is not suitable for charging into a furnacefor remelting, unless it is in free-flowing shovelling size. It istherefore necessary to crush or shred the tumings to grain or pelletsize pieces, known as fines, in order to reduce the volume thereof andto facilitate magnetic or other separation. Since the metal tumings arepicked up from machine shop floors and the like, they are usually amixture of different metals having different physical properties. Forinstance, in one cluster of tumings there may be soft aluminum tumingsmixed with spring steel turnings, thus complicating the crushingoperation. Crushers used for shredding or crushing, pulverizing orgrinding metal tumings are for example, of the type shown in US. Pat.Nos 1,862,889 and 1,947,700 to the American Pulverizer Co. Althoughcrushers of this type are very effective in crushing metal turnings theymay break if heavy solid pieces are mixed or hidden in the tumings, andare often jammed when a relatively large cluster of bunched metalturnings passes into the crusher. It is then necessary to literallydismount the crusher for repairs or to remove the cluster whichhasjammed it.

On the other hand, if solid chunks are removed and the size of theclusters of bunched metal tumings are controlled in size and the rate atwhich they are being fed, then the frequency of breaking or crusherjamming can be greatly reduced or eliminated.

OBJECT OF THE INVENTION It is an aim of the present invention to providean apparatus and method of removing the solid chunks and reducing thesizes of said clusters and to control the rate at which the metaltumings are fed to the crusher.

A construction in accordance with the present invention comprisesconveying means for conveying the metal tumings. The conveying meansincludes teeth adapted to engage the metal tumings, support meansopposed and spaced from said conveying means and teeth mounted on saidsupport means. The latter teeth are adapted to engage large clusters ofbunched metal turnings, whereby there is relative longitudinal movementbetween the teeth on said conveying means tending to shred the clustersengaged by the teeth on the conveying means and the teeth on the supportmeans.

In a preferred embodiment, the above-mentioned apparatus is locatedimmediately preceding a metal turnings crusher whereby the size and rateof the metal turning and clusters to the crusher can be controlled. In apreferred embodiment it is also contemplated to pass the metal tumingsfirst through a rotating perforated drum whereby the metallic finesalready formed are discharged centrifugally from the drum and can becollected and only the solids and clustered tumings will be separatedand discharged axially onto an inspection table whereby the solids canbe seen and removed and the clusters advanced by gravity towards theconveying means.

A method in accordance with the present invention includes the steps ofpassing the metal tumings through a separator stage where the fine loosemetal turnings are separated from the solid chunks and the clusters,removing the solids, and passing the remaining clusters of metal tumingsto a conveyor station, conveying the metal tumings forward towards acrushing station, shredding the large clusters of metal tumings as theyare being advanced, whereby the large clusters are reduced to a sizesuitable for crushing and finally crushing the metal turnings.

BRIEF DESCRIPTION OF THE DRAWINGS Having thus generally described thenature of the invention, particular reference will be made to theaccompanying drawings showing by way of illustration, preferredembodiments thereof and in which:

FIG. 1 is a schematic plan view illustrating one embodiment of theinvention;

FIG. 2 is a schematic elevation of the arrangement shown in FIG. 1;

FIG. 3 is a side elevation of a detail shown in FIG. 1;

FIG. 4 is a vertical cross section taken along the lines 4-4 of FIG. 3;

FIG. 5 is a top plan view of another detail taken from FIG.

FIG. 6 is a side elevation of the detail shown in FIG. 5;

FIG. 7 is a vertical cross section taken along lines 77 of FIG. 6;

FIG. 8 is a vertical cross section taken along lines 8-8 in FIG. 5;

FIG, 9 is a fragmentary perspective view of a detail of the apparatusshown in FIGS. 5 through 8;

FIG. 10 is an end elevation taken through the intake end of theapparatus shown in FIGS. 5 through 8; and

FIG. 11 is a perspective view of the discharge end of the apparatusshown in FIGS. 5 through 8.

Referring now to FIGS. 1 and 2, the combination shown includes a rawmaterial intake hopper 10 in which the metal tumings are fed, while theconveyor 12 conveys the metal turnings from the hopper 10 towards therotating separator drum 14. The material which has not been dischargedfrom the separating drum 14 is discharged onto an inspection table 16which is in the form of a slide which conducts the metal turnings bygravity from the separating drum 14 to the shredding apparatus 20. Ashredding apparatus which reduces the sizes of the clusters of bunchedmetal tumings and discharges the metal tumings into a delivery chute 22which in turn conducts the metal tumings into a crusher 24 is provided.Any suitable crusher, pulverizer or grinder can of course be used.Discharge from the crusher l3 falls onto a discharge conveyor 26 whichcarries crushed tumings as well as the fines from the separating drum 14towards a subsequent step which can include a storage bin or conveyance.

Referring now to FIGS. 3 and 4, a separating drum 14 is shown having anintake 27 and a discharge 29. The separating drum 14 includes acylindrical drum 28 having a plurality of apertures 30. Gear tracks 32are provided near each end of the cylinder 28 and are adapted to beengaged by gears 33 fixed to drive shafts 34 on either side of thecylinder 28. The drive shafts 34 are joumalled for rotation in bearings36 (and are driven by a motor 38), via gear box 31 and chain andsprocket drive 35.

In operation, as the metal tumings are fed from the conveyor 12 into theintake end 27 of the separating drum 14, they are rotated within thedrum and are caused to jog around in the cylindrical drum 28 by means ofdeflector plates 40. The fines are discharged through the apertures 30while the solid chunks are separated from the clusters by centrifugalforce.

The remaining clusters of metal tumings and solids are dischargedthrough the discharge opening 29 of the separating drum 14 by gravitysince the axis of the separating drum is inclined onto an inspectiontable 16 which is in the shape of a curved chute which is also inclinedto allow the clusters of metal tumings to slide downwardly towards theintake end of the shredding apparatus 20. The inspection table 16includes a smooth table surface 42 which is curved and inclined as shownin FIG. 1 and mounts side walls 44 to prevent the metal tumings fromfalling 'off the inspection table 16. While the clusters of metaltumings advance on the inspection table 16, the operator can at thisstage remove any metallic chunks which would normally not have to becrushed by the crusher and which would unnecessarily burden the crushingoperation or break the crusher. The shredding apparatus 20 (as shown inFIGS. 5 to 11) is mounted on a frame 48 and includes an upwardlyinclined smooth table surface 50. Driven chain engaging gears 52 and 54are provided at the intake end of the shredding apparatus 20. Thesedriven chain engaging gears 52 and 54 are fixed at each end of a drivenshaft 56. Idler gears 58 and 60 which are mounted on an idler shaft 52aare provided at the other end of the table surface 50 and idler gears64, 65 mounted on the shaft 66 are spaced downwardly slightly from theidler gears 58 and 60. Endless chains 68 and 70 are located about thegears 52, 58, 64 and 54, 60 and 65 respectively. Lateral bars 72a, 72bto 72i are connected laterally to the respective endless chains 68 and70 as shown in FIGS. 7 and 9. A plurality of upwardly extending teeth 74are welded to the lateral bars 72.

A drive gear 76 is fixedly connected to the drive shaft 56 which mountsthe driven chain engaging gears 52 and 54 and is in turn driven by achain 78 connected to a gear mounted in reduction box 80. Large gear 82driven by chain 86 passing about the large gear 82 and a smaller gear 84drives the gearing in the reduction box 80 and is in turn driven by amotor 88.

Side walls 90 and 92 are provided on either side of the inclined tablesurface 50 and are structurally reinforced to mount hinged top wallhalves 94 and 96. These hinged top wall halves are adapted to openoutwardly pivoting about the upper edge of the side walls 90 and 92respectively to expose the inclined table surface 50 as well as thechains 68, 70 and the teeth 74. In its operating position hinged topwall halves 94 and 96 are normally closed over the inclined tablesurface 50 and are locked there by means of locking bars 98 passingthrough apertures in projections 100 on the exterior surface of thetable top halves 94 and 96. Each table top half 94 and 96 mountsdownwardly extending projecting teeth 102 which are interspaced with theupwardly extending teeth 74. These teeth 102 are of course stationary inthe present embodiment while the teeth 74 on the bar 72 are adapted tomove longitudinally forward relative to the stationary teeth 102. Asclusters of bunched metal turnings are fed into the intake end of theshredding apparatus, the teeth 74 engage these clusters to advance themforward along the inclined table surface 50. However, downwardlyextending teeth 102 which are spaced upwardly a predetermined distancefrom the inclined table surface 50 and also engage the clusters whichare too large and the relative movement of the teeth 74 relative to theteeth 102 causes the clusters to be shredded or at least break up intosmaller clusters. These smaller metal turning clusters are thendischarged by the teeth 74 mounted on bar 72 into a discharge chute 22.

In order to control the rate of feed of the clusters of metal turningsinto the crusher, a guillotine arm 104 is pivotally mounted at theintake end of the shredding apparatus 20. The guillotine arm 104 mountsa plurality of teeth 106 and the free end of the guillotine arm 104moves in the guide slot 108 provided on the opposite lateral side of theshredding apparatus intake end. When it is required to reduce the feedof metal turnings into the crusher, the guillotine can be lowered into aposition shown in FIG. 10, causing the clusters of metal filings to backup on the inspection table 16. The guillotine arm 104 can be manuallyoperated and in the case of an extremely large cluster of metalturnings, it can be used too as a means to reduce the size of thecluster as it enters the intake end of the shredding apparatus.

At the discharge end of the shredding apparatus, there is provided apair of frame extension arms 110 and 1 12. A pivot shaft 116 is mountedfor rotation between the arms 110 and 112 and fixedly mounts a pivotingbaffle plate 114. A lever arm 118 is fixedly connected to the pivotshaft 116 and is attached to a rope 120 which in turn passes over apulley 122 and is connected to a collar 128 in a counterweight housing124 and either mounts a plurality of weights or works against a spring126 as shown in the present embodiment.

The pivoting plate 144 is normally in a vertical position but as a setof teeth 74 on a bar 72 passes they abut against the plate 114 causin itto pivot resiliently against its counter weight system. [S pivotingplate 114 acts to clean the conveyor chains 68 and 70 of the metalturnings which tend to move along the return run of the endless chain 68and 70/72 and 74.

The metal turnings are discharged in the discharge chute 22 and enterthe crusher 24. The crusher 24 is not shown here in detail but can be ofthe type mentioned above with respect to U.S. Pat. Nos. 1,947,700 and1,860,889.

From the apparatus described in the present embodiment, it can be seenthat the metal turnings, which are normally bunched in clusters, willhave been reduced in size, if they are oversized, by means of theshredding apparatus 15, and they will have been previously cleaned offines and metal chunks as they pass through the separating drum 14 andthe inspection table 16.

I claim:

1. A method of reducing metal turnings to fines which can beeconomically handled and remelted, including passing the metal turningsthrough a separating stage wherein the metal turnings are subjected tocentrifugal force in an attempt to separate the fines and chunks fromthe metal clusters, removing the chunks, passing the remaining clustersthrough a conveyor station, conveying the metal turnings in saidconveyor station to a crushing station, shredding large clusters ofmetal turnings as they are being advanced towards the crusher wherebythe large clusters are reduced to a size suitable for crushing, finallycrushing the metal turnings to fines.

2. A method as defined in claim 1, wherein the step of shredding largeclusters of metal turnings at the conveyor station includes partiallyretaining the clusters and partially gripping the same clusters by theconveyor so as to reduce the size of the clusters by such shredding.

2. A method as defined in claim 1, wherein the step of shredding largeclusters of metal turnings at the conveyor station includes partiallyretaining the clusters and partially gripping the same clusters by theconveyor so as to reduce the size of the clusters by such shredding.